A radiological imaging sensor typically comprises a semiconductor chip having an array of photosensitive pixels, each pixel including a photodetector and an active amplifier, a scintillator covering the chip and a fiber optic plate positioned between the scintillator and the semiconductor chip. The scintillator layer converts incoming X-rays into visible light. The above-described elements of the radiological imaging sensor may be contained in a package from which a connection cable may extend to a computer system for processing acquired images.
FIG. 1 is a cross sectional view of a prior art radiological imaging sensor 100 having Kovar substrate 101 and based on a thermal-cured adhesive process. Imaging die 104 having an active sensor area 105 is stacked on top of Kovar substrate 101, and is secured in place thereon by a thermally cured adhesive layer 103. Similarly, fiber optic plate 106 is stacked on imaging die 104, and is secured in place using thermally cured adhesive layer 110. It is noted that the thermal cure process is very batch oriented, and also very time-consuming, in the order of 12 to 18 hours per cycle typically. It is evident that typically 2 thermal cure cycles may be required in assembling imaging sensor 100. Scintillator layer 107 may be either a deposited layer, or else may be applied as a paper strip, secured appropriately in place using a press-on cover. Kovar substrate 101, more expensive than a clear glass substrate typically by a factor of around 100 times, is typically selected to minimize thermal mismatch effects generated during the thermal cycles for adhesive thermal curing in assembly and construction of radiological imaging sensor 100.
Those skilled in the art will appreciate that a special bonding post 108 must be provided in order to form wire bond connection 109 for any flexible cable connections to imaging sensor 100.